Abstract: Time duration of hot pressing determines not only the quality of the plye wood, but also the productivity of hot press. The required length of time duration of hot pressing chiefly depends on the rising speed of the temperature in the glueline. This paper deals with the regular patterns of the rising of temperature in the glueline during hot pressing and its relationship with the shear strength of the plywood. Our tests show: 1. The changes of temperature in the glueline can be divided into three stages: fast rising, slow rising and dropping. 2. After the temperature is raised to 100-, the glueline should be continuously heated for some time. However, excessive heating can decrease the shear strength of the plywood. 3. When thicker plies are used, lower temperatures should be applied.